Multicylinder tanks

ABSTRACT

A tank having an outer wall comprising a plurality of intersecting vertical cylindrical segments joined together at the intersection and arranged with their concave surfaces facing inwardly. Webs joined to junctures of the cylindrical segments and extending across the tank to other junctures carry a part of the outward force applied to the outer wall by liquids stored in the tank.

lPattenll Phelps [54] MlJLTllCl/LHNUER TANKS [72] Inventor: Rex V.Phelps, Tulsa, Okla.

[73] Assignee: Warren Petroleum Corporation, Tulsa,

Okla.

[22] Filed: Apr. 23, 11970 [2]] Appl. No.: 31,311

[52] US. Cl ...2220/22, 220/1 B, 220/71 [51] lint. 1C1 .Jll65dl 11/24[58] lFieltl of Search ..220/2l, 20, 22, 1 B, 71, 18, 220/3 [56]llleierenees Cited UNITED STATES PATENTS 1,668,179 5/1928 Williams..220/7l 3,528,582 9/1970 Rigollot ...220/71 X 2,860,806 11/1958Yanowitz ..220/1 B 3,314,567 4/1967 Becker et al.. ..220/7l X 1,864,7596/1932 Pritchard ..220/1 B Well. 29, 1972 2,341,044 2/1944 Jackson et a1..220/71 112 3,112,044 11/1963 Larsen et a1. .220/18 3,528,582 9/1970Rigollot ..220/71 X FOREIGN PATENTS OR APPLlCATlONS 612,213 11/1960ltaly .220/l B Primary Examiner-loseph 1R. Leclair AssistantExaminer-James R. Garrett Attorney-Meyer Neishloss, Deane E. Keith andPaul L. Tillson [57] ABSTRACT A tank having an outer wall comprising aplurality of intersecting vertical cylindrical segments joined togetherat the intersection and arranged with their concave surfaces facinginwardly. Webs joined to junctures of the cylindrical segments andextending across the tank to other junctures carry a part of the outwardforce applied to the outer wall by liquids stored in the tank.

3 Claims, 5 Drawing ll iggnres Pmmmrme m2 3, msm s SHEET 2 OF 2MULTICYLINITIEEI TANKS This invention relates to the storage of liquidsand more particularly to storage tanks of large capacity for storingliquids at atmospheric pressure.

The increased consumption of petroleum products has made necessaryterminals of large capacity. Formerly the terminals consisted of a largenumber of relatively small flat-bottomed, vertical cylindrical tanks ofabout 50,000 barrels each. The term vertical cylindrical is used todesignate tanks of cylindrical shape with the axis of the cylindervertical. As a safety measure, firewalls are constructed around each ofthe tanks to prevent flow of burning hydrocarbons from one tank toanother if petroleum products in one tank should start burning. Thefirewalls add substantially to the area required for each tank.

To reduce the space requirements for terminals, the size of theindividual tanks has been increased, and at present vertical cylindricaltanks having a capacity as high as approximately 1,000,000 barrels havebeen constructed. Such tanks have a diameter of approximately 300 feetand a height of the order of 80 feet. The head of liquid in such a tankand the large diameter of the tank have made it necessary for bottomrings of the tank to be as thick as 3 inches to withstand the resultingtensile stresses in the tank wall. The handling of 3-inch steel plateand the welding of plate of such thickness on site during theconstruction of the tank cause the cylindrical tanks of large capacityto be very expensive.

Recently tankers having a capacity larger than 2,000,000 barrels havecome into use. Those tankers are equipped with high-capacity pumpscapable of pumping oil at a rate approaching 100,000 barrels per hour.Because of the high pumping rate, tanks of increased capacity aredesired to reduce the frequency of switching from one tank to anotherduring the unloading operation, and thereby to reduce the danger ofspills.

This invention resides in flat-bottom storage tanks of large capacityadapted to store liquids at atmospheric pressure in which a plurality ofvertical cylindrical segments arranged concave inwardly are welded tothe bottom and to one another along elements of the cylinders to formthe sidewalls of the tank. Webs joined to opposing junctures ofcylindrical segments extend across the tank. The webs bear a portion ofthe tensile stress that would otherwise be borne entirely by the wall ofthe tank and also provide a support for the tank roof. An importantadvantage of the tanks of this invention is the flexibility in the shapeand size of the tank which allows effi cient use of the space availableat a terminal.

In the drawings:

FIG. l is a horizontal sectional view along section line Il in FIG. 2 ofa tank constructed in accordance with this invention.

FIG. 2 is a vertical sectional view along section line II-II in FIG. Iof the embodiment of the invention illustrated in FIG. I.

FIG. 3 is a plan view of a storage tank, with the top removed,illustrating this invention in a multicylinder tank of large capacity.

FIG. t is a plan view similar to FIG. 3 of another embodiment of thisinvention.

FIG. 5 is a plan view similar to FIG. 3 of an L-shaped tank utilizingthis invention.

Referring to FIG. l, a tank indicated generally by reference numeral I0has four vertical cylindrical segments ll2a, 112b, l2c and 12d welded toone another along elements of the cylinders at their lateral edges toform the sidewall of the tank extending for the full periphery of thetank. The cylindrical segments are welded at their lower end to thebottom of the tank and are arranged with their concave surfaces facinginwardly. Cylindrical segments 12a and l2b are welded along elements atjuncture I4}, 12b and 112s are welded at juncture l6, 12c and 32d arewelded at juncture l8, and 12d and T are welded at juncture 20.

Welded to cylindrical segments 12a and 11215 at juncture M is a web 22which extends across the tank T0 to juncture l0 where web 22 is weldedto cylindrical segments I20 and ll2d. A similar web 24 is welded atjuncture 20 to cylindrical segments Mia and 12d and extends across thetank T0 to juncture lb where it is welded to segments llllb and 12c. Inthe manufacture of the tank it is contemplated that the webs 22 and 24will be erected on the bottom of the tank and the weld at each juncturemade to join the cylindrical segments and the webs simultaneously. Inactual construction, web 24 will consist of two parts. One part willextend from juncture 20 to the midpoint of web 22 and the other fromthat midpoint to juncture l6.

As shown in FIG. 2 it is contemplated that the tank walls will beconstructed of a series of horizontal bands such as bands as, 20, 30 and32. In accordance with conventional practice, the thickness of the bandsis largest near the bottom of the tank and decreases toward the top ofthe tank. Similarly, the webs may be constructed of a series of stripsM, Ilti, 30, and 410 of successively decreasing thickness. As shown inFIG. 2, the webs have openings l2 near their bottom to permit flow fromone portion of the tank to another.

In the tank illustrated in FIGS. l1 and 2, the cylindrical segments112a, ll2b, I20 and I20! should include an arc exceeding It is preferredthat the arc of each of the cylindrical segments be in the range of 1 10to With that arrangement the radius of each of the cylindrical segmentsis smaller than the radius of a cylinder having the same cross-sectionalarea as the tank T0. The small radius contributes to the rigidity of thetank and permits more effective use of the space at the terminal becausethe shape of the tank is more nearly square than is a circle. With thearcs of the cylindrical segments being in the range of I I0? to 160, theinternal angle between the webs and the tank walls exceeds 90.

In the embodiment of the invention illustrated in FIG. 3, a tank 50 hascorner cylindrical segments 46a, lhb, 46c and ldd welded to the bottom47 at each of the comers of the tank which is of an overall generallyrectangular shape. The space between the lateral edges of the cornercylindrical segments is closed by linearly aligned series 40a, 40b, 48cand 40d of widening cylindrical segments 49a, 4%, 490, and 49d,respectively. Each of the corner cylindrical segments 46a, 46b, The, andlbd is welded along the element of the cylinder at each of its lateraledges to the lateral edge of the end widening strip in a series to formjunctures 50. Each of the widening strips is welded to the adjacentwidening strip in the series to form junctures 52. Webs 54a extendacross the tank from juncture 50 to an opposite juncture 50, and websS-tib extend across the tank from a juncture 52 to an opposite juncture52. As in the embodiment of the invention illustrated in FIG. 2, it iscontemplated that the web structure illustrated in FIG. 3 will beconstructed on the bottom d7" of the tank, and the joining of the weband the cylindrical segments :at each juncture will be madesimultaneously. As shown in FIG. 3, all of the cylindrical elements 46and 49 are arranged with their concave surfaces facing inwardly to formtank sidewalls of lobular shape.

In the embodiment of the invention illustrated in FIG. 3, the cornercylindrical segments doa, 46b, doc and 46d preferably include an arc inthe range of 1 10 to The are included by the widening strips 49a, 49b,Awe, and 0%, etc., is preferably equal to the number of degrees thecorner segments exceed 90 and the radius of curvature of the wideningsegments is the same as the radius of curvature of the corner segmentsto give a structure in which the widening cylindrical segments and thecorner cylindrical segments have a common tangent. The embodiment of theinvention illustrated in FIG. 3 has been shown for a tank of rectangularshape. This invention is advantageous in allowing flexibility in theshape of the tank to allow the tank to fit the site available.

In the storage tank indicated generally by reference numeral 56illustrated in FIG. l, a plurality of cylindrical segments 58 arearranged to extend vertically upward from a tank bottom 60. Thecylindrical segments 58 are in linear alignment and are joined along anelement of the cylinders. Similarly, cylindrical segments 62 arearranged in linear alignment at right angles to the alignment of thecylinders 58 and are welded one to another along their vertical edges.Cylindrical segments 64 are arranged parallel to and spaced fromsegments 50 and are welded one to another along their vertical edges.Another series of vertical cylindrical segments 66 are arranged inlinear alignment parallel to cylindrical segments 62 and are welded oneto another along an element in their vertical edges. The free ends ofthe four series of cylindrical segments are welded together at junctures68, 70, 72 and 74 to form the completed sidewalls of the tank.

Webs 76 extend across the tank from the junctures 78 of the cylindricalelements 58 to the junctures of the cylindrical elements 64. Similarly,webs 82 extend across the tank and are joined to cylindrical elements 66at junctures 84 and to cylindrical elements 62 at elements 86. Webs 85'extend diagonally inward from junctures 68, 70, 72, and 741 and areconnected to junctures of webs 78 and 82. Webs 76, 82) and 85 and thesidewalls provide support for a roof, not shown in the drawing. Theembodiment of the invention illustrated in FIG. 4 is composed of aplurality of cylindrical segments, all of which include an arc of 180.Since all of the cylindrical segments in the tank illustrated in FIG. 4are identical, fabrication and erection of the tank is simplified. Itwill be noted that the tank illustrated in FIG. 4 is of generallyrectangular shape but that the corners consist of two cylindricalsegments rather than a single cylindrical segment as shown in theembodiment illustrated in FIG. 3.

In the embodiment illustrated in FIG. 5, an L-shaped tank indicatedgenerally by reference numeral 90 is illustrated with corner cylindricalsegments 92 at each of the external comers of the tank. The termexternal corners is used to to denote corners at which the externalangle of the sidewalls meeting at the corner exceeds 180". No cornercylindrical element is required at the internal comer at which the twolegs of the ell meet. Each of the lateral edges is welded to a series ofvertical linearly aligned cylindrical segments 94 welded together toform the sidewalls of the tank. Webs 96 extend across the tank and areconnected to the junctures of the cylindrical segments.

The storage tank constructed in accordance with this invention is usefulfor tanks having a capacity exceeding 500,000 barrels and isparticularly advantageous in providing a tank having a capacity inexcess of 1,000,000 barrels. Tanks can be constructed using the conceptof this invention of unlimited size without excessive wall thicknessesat the lower portion of the tank. Although steel is required for thewebs extending across the tank, the webs carry part of the tensile loadcarried entirely by the tank wall in single cylinder tanks and permitreduction in wall thickness of the tank. Thus, the tank structurerequires no more steel than single cylinder tanks and avoids the verythick, difficult to handle wall sections required by vertical singlecylinder tanks of large capacity.

An important advantage of this invention is the saving in space at aterminal site required for the storage tanks. The generally rectangularor square shape of the tanks and the very large size of the tanks allowthe tanks to occupy a higher percentage of the space within thefirewalls. The large tanks constructed according to this inventionreduce the amount of switching from one tank to another during theloading of a tanker and thereby reduce the danger of spill oroverflowing of tanks.

I claim:

1. A tank having a capacity of at least 500,000 barrels for the storageof liquid at atmospheric pressure comprising a flat bottom of generallyoverall polygonal shape with each side substantially perpendicular tosides adjacent thereto, a vertically extending comer cylindrical segmenthaving a circular arcuate-shaped horizontal cross section of to weldedto the bottom at each external corner thereof and extending upwardlytherefrom, said comer cylindrical segments being arranged concaveinwardly, a plurality of series of vertically extending cylindricalsegments of circular arcuateshaped horizontal cross section with thesame radius of curvature as that of the corner cylindrical segments andincluding the number of degrees by which the corner cylindrical segmentseach exceed 90 welded together in linear alignment along the edgeelements thereof and welded to the bottom of the tank to form thesidewalls of the tank with the cylindrical segments concave inwardly,each of said series being welded to a vertical edge of one cornercylindrical segment and extending to and welded to the nearest verticaledge of an adjacent comer cylindrical segment, a single web secured ateach juncture of the cylindrical segments and extending inwardly acrossthe tank to a juncture of cylindrical segments in the opposite sidewallof the tank, and a roof supported over the tank by the upper ends ofwebs.

2. A tank as set forth in claim l in which the tank is of generaloverall rectangular shape in horizontal section.

3. A tank having a capacity of at least 500,000 barrels for the storageof liquid at atmospheric pressure comprising a flat bottom of L-shapewith each side substantially perpendicular to sides adjacent thereto, avertically extending cylindrical segment having a circulararcuate-shaped horizontal cross section welded to the bottom at eachexternal corner thereof and extending upwardly therefrom, said cornercylindrical segments being arranged concave inwardly, a plurality ofseries of vertically extending cylindrical segments of circulararcuateshaped horizontal cross section welded together in linearalignment along the edge elements thereof and welded to the bottom ofthe tank to form the sidewalls of the tank with the cylindrical segmentsconcave inwardly, each of said series being welded to a vertical edge ofone corner cylindrical segment and extending to and welded to thenearest vertical edge of an adjacent corner cylindrical segment, asingle web secured at each juncture of the cylindrical segments andextending inwardly across the tank to a juncture of cylindrical segmentsin the opposite sidewall of the tank, two cylindrical elements of two ofthe series of cylindrical elements being joined together at the internalangle of the L, and a web from this juncture at the internal angle joinsand extends inwardly to another web, and a roof supported over the tankby the upper ends of the webs.

1. A tank having a capacity of at least 500,000 barrels for the storageof liquid at atmospheric pressure comprising a flat bottom of generallyoverall polygonal shape with each side substantially perpendicular tosides adjacent thereto, a vertically extending corner cylindricalsegment having a circular arcuate-shaped horizontal cross section of110* to 160* welded to the bottom at each external corner thereof andextending upwardly therefrom, said corner cylindrical segments beingarranged concave inwardly, a plurality of series of vertically extendingcylindrical segments of circular arcuate-shaped horizontal cross sectionwith the same radius of curvature as that of the corner cylindricalsegments and including the number of degrees by which the cornercylindrical segments each exceed 90* welded together in linear alignmentalong the edge elements thereof and welded to the bottom of the tank toform the sidewalls of the tank with the cylindrical segments concaveinwardly, each of said series being welded to a vertical edge of onecorner cylindrical segment and extending to and welded to the nearestvertical edge of an adjacent corner cylindrical segment, a single websecured at each juncture of the cylindrical segments and extendinginwardly across the tank to a juncture of cylindrical segments in theopposite sidewall of the tank, and a roof supported over the tank by theupper ends of webs.
 2. A tank as set forth in claim 1 in which the tankis of general overall rectangular shape in horizontal section.
 3. A tankhaving a capacity of at least 500,000 barrels for the storage of liquidat atmospheric pressure comprising a flat bottom of L-shape with eachside substantially perpendicular to sides adjacent thereto, a verticallyextending cylindrical segment having a circular arcuate-shapedhorizontal cross section welded to the bottom at each external cornerthereof and extending upwardly therefrom, said corner cylindricalsegments being arranged concave inwardly, a plurality of series ofvertically extending cylindrical segments of circular arcuate-shapedhorizontal cross section welded together in linear alignment along theedge elements thereof and welded to the bottom of the tank to form thesidewalls of the tank with the cylindrical segments concave inwardly,each of said series being weLded to a vertical edge of one cornercylindrical segment and extending to and welded to the nearest verticaledge of an adjacent corner cylindrical segment, a single web secured ateach juncture of the cylindrical segments and extending inwardly acrossthe tank to a juncture of cylindrical segments in the opposite sidewallof the tank, two cylindrical elements of two of the series ofcylindrical elements being joined together at the internal angle of theL, and a web from this juncture at the internal angle joins and extendsinwardly to another web, and a roof supported over the tank by the upperends of the webs.